"Aliana has never had any type of plastic surgery in her life, nor has she ever considered it," her rep Steve Honig tells PEOPLE, insisting that the perceived changes in Lohan's face are purely natural.

"Her success as a model lies with her natural looks and she has no interest in changing that," the statement continues. "During the past two years, she has gone through a normal teenage growth spurt that has made her taller and slimmer."

The younger Lohan, 17, has been the subject of chatter after stepping out with a noticeably thinner frame and a more drawn appearance.

Lohan's growth "has also slightly changed the composure of her face, all of which is typical of what happens to kids in their mid to late teens," explains Honig. "It's what most people refer to as the awkward stage. Ali is growing up; that's all."

Her modeling agency rep also denied Lohan had plastic surgery.

"As a young girl who is growing up, it's natural for her facial features to change slightly, and we see this with many of the younger models we represent," says Alexis Borges, agency director of Next Model Management L.A. "Aliana is a beautiful 17 year old girl who is growing into her face and body, as is the norm for someone of her age."

Borges adds: "We take pastoral care of our models very seriously and encourage the models to maintain a healthy lifestyle and body shape."